2 * 11/19/04 : 1.0 moved to LGPL.
3 * VBRI header support added, E.B javalayer@javazoom.net
5 * 12/04/03 : VBR (XING) header support added, E.B javalayer@javazoom.net
7 * 02/13/99 : Java Conversion by JavaZOOM , E.B javalayer@javazoom.net
9 * Declarations for MPEG header class
10 * A few layer III, MPEG-2 LSF, and seeking modifications made by Jeff Tsay.
11 * Last modified : 04/19/97
13 * @(#) header.h 1.7, last edit: 6/15/94 16:55:33
14 * @(#) Copyright (C) 1993, 1994 Tobias Bading (bading@cs.tu-berlin.de)
15 * @(#) Berlin University of Technology
16 *-----------------------------------------------------------------------
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU Library General Public License as published
19 * by the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU Library General Public License for more details.
27 * You should have received a copy of the GNU Library General Public
28 * License along with this program; if not, write to the Free Software
29 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
30 *----------------------------------------------------------------------
34 * Class for extracting information from a frame header.
37 public final class Header {
39 public static final int[][] frequencies = { { 22050, 24000, 16000, 1 }, { 44100, 48000, 32000, 1 }, { 11025, 12000, 8000, 1 } }; // SZD:
43 * Constant for MPEG-2 LSF version
45 public static final int MPEG2_LSF = 0;
46 public static final int MPEG25_LSF = 2; // SZD
49 * Constant for MPEG-1 version
51 public static final int MPEG1 = 1;
53 public static final int STEREO = 0;
54 public static final int JOINT_STEREO = 1;
55 public static final int DUAL_CHANNEL = 2;
56 public static final int SINGLE_CHANNEL = 3;
57 public static final int FOURTYFOUR_POINT_ONE = 0;
58 public static final int FOURTYEIGHT = 1;
59 public static final int THIRTYTWO = 2;
63 private int h_protection_bit;
65 private int h_bitrate_index;
67 private int h_padding_bit;
69 private int h_mode_extension;
71 private int h_version;
75 private int h_sample_frequency;
77 private int h_number_of_subbands;
79 private int h_intensity_stereo_bound;
81 private boolean h_copyright;
83 private boolean h_original;
84 // VBR support added by E.B
86 private double[] h_vbr_time_per_frame = { -1.0, 384.0, 1152.0, 1152.0 };
88 private boolean h_vbr;
90 private int h_vbr_frames;
92 private int h_vbr_scale;
94 private int h_vbr_bytes;
96 private byte[] h_vbr_toc;
98 private byte syncmode = Bitstream.INITIAL_SYNC;
102 public short checksum;
104 public int framesize;
108 private int _headerstring = -1; // E.B
110 private SideInfoBuffer sib;
112 private BitReserve br;
120 public String toString() {
121 StringBuffer buffer = new StringBuffer(200);
122 buffer.append("Layer ");
123 buffer.append(layer_string());
124 buffer.append(" frame ");
125 buffer.append(mode_string());
127 buffer.append(version_string());
129 buffer.append(" no");
130 buffer.append(" checksums");
132 buffer.append(sample_frequency_string());
135 buffer.append(bitrate_string());
137 String s = buffer.toString();
143 * Read a 32-bit header from the bitstream.
145 int read_header(Bitstream stream, Crc16[] crcp) throws BitstreamException {
148 boolean sync = false;
150 headerstring = stream.syncHeader(syncmode);
151 if (headerstring == -1) {
154 _headerstring = headerstring; // E.B
155 if (syncmode == Bitstream.INITIAL_SYNC) {
156 h_version = ((headerstring >>> 19) & 1);
157 if (((headerstring >>> 20) & 1) == 0) // SZD: MPEG2.5 detection
158 if (h_version == MPEG2_LSF)
159 h_version = MPEG25_LSF;
161 throw stream.newBitstreamException(Bitstream.UNKNOWN_ERROR);
162 if ((h_sample_frequency = ((headerstring >>> 10) & 3)) == 3) {
163 throw stream.newBitstreamException(Bitstream.UNKNOWN_ERROR);
166 h_layer = 4 - (headerstring >>> 17) & 3;
167 h_protection_bit = (headerstring >>> 16) & 1;
168 h_bitrate_index = (headerstring >>> 12) & 0xF;
169 h_padding_bit = (headerstring >>> 9) & 1;
170 h_mode = ((headerstring >>> 6) & 3);
171 h_mode_extension = (headerstring >>> 4) & 3;
172 if (h_mode == JOINT_STEREO)
173 h_intensity_stereo_bound = (h_mode_extension << 2) + 4;
175 h_intensity_stereo_bound = 0; // should never be used
176 if (((headerstring >>> 3) & 1) == 1)
178 if (((headerstring >>> 2) & 1) == 1)
180 // calculate number of subbands:
182 h_number_of_subbands = 32;
184 channel_bitrate = h_bitrate_index;
185 // calculate bitrate per channel:
186 if (h_mode != SINGLE_CHANNEL)
187 if (channel_bitrate == 4)
190 channel_bitrate -= 4;
191 if ((channel_bitrate == 1) || (channel_bitrate == 2))
192 if (h_sample_frequency == THIRTYTWO)
193 h_number_of_subbands = 12;
195 h_number_of_subbands = 8;
196 else if ((h_sample_frequency == FOURTYEIGHT) || ((channel_bitrate >= 3) && (channel_bitrate <= 5)))
197 h_number_of_subbands = 27;
199 h_number_of_subbands = 30;
201 if (h_intensity_stereo_bound > h_number_of_subbands)
202 h_intensity_stereo_bound = h_number_of_subbands;
203 // calculate framesize and nSlots
204 calculate_framesize();
206 int framesizeloaded = stream.read_frame_data(framesize);
207 if ((framesize >= 0) && (framesizeloaded != framesize)) {
208 // Data loaded does not match to expected framesize,
209 // it might be an ID3v1 TAG. (Fix 11/17/04).
210 throw stream.newBitstreamException(Bitstream.INVALIDFRAME);
212 if (stream.isSyncCurrentPosition(syncmode)) {
213 if (syncmode == Bitstream.INITIAL_SYNC) {
214 syncmode = Bitstream.STRICT_SYNC;
215 stream.set_syncword(headerstring & 0xFFF80CC0);
219 stream.unreadFrame();
222 stream.parse_frame();
223 if (h_protection_bit == 0) {
224 // frame contains a crc checksum
225 checksum = (short) stream.get_bits(16);
228 crc.add_bits(headerstring, 16);
232 if (h_sample_frequency == FOURTYFOUR_POINT_ONE) {
234 * if (offset == null) { int max = max_number_of_frames(stream); offset =
235 * new int[max]; for(int i=0; i<max; i++) offset[i] = 0; } // E.B :
236 * Investigate more int cf = stream.current_frame(); int lf =
237 * stream.last_frame(); if ((cf > 0) && (cf == lf)) { offset[cf] =
238 * offset[cf-1] + h_padding_bit; } else { offset[0] = h_padding_bit; }
245 * Parse frame to extract optionnal VBR frame.
248 * @author E.B (javalayer@javazoom.net)
250 void parseVBR(byte[] firstframe) throws BitstreamException {
251 // Trying Xing header.
252 String xing = "Xing";
253 byte tmp[] = new byte[4];
255 // Compute "Xing" offset depending on MPEG version and channels.
256 if (h_version == MPEG1) {
257 if (h_mode == SINGLE_CHANNEL)
262 if (h_mode == SINGLE_CHANNEL)
268 System.arraycopy(firstframe, offset, tmp, 0, 4);
270 if (xing.equals(new String(tmp))) {
276 h_vbr_toc = new byte[100];
280 byte flags[] = new byte[4];
281 System.arraycopy(firstframe, offset + length, flags, 0, flags.length);
282 length += flags.length;
283 // Read number of frames (if available).
284 if ((flags[3] & (byte) (1 << 0)) != 0) {
285 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
286 h_vbr_frames = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
289 // Read size (if available).
290 if ((flags[3] & (byte) (1 << 1)) != 0) {
291 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
292 h_vbr_bytes = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
295 // Read TOC (if available).
296 if ((flags[3] & (byte) (1 << 2)) != 0) {
297 System.arraycopy(firstframe, offset + length, h_vbr_toc, 0, h_vbr_toc.length);
298 length += h_vbr_toc.length;
300 // Read scale (if available).
301 if ((flags[3] & (byte) (1 << 3)) != 0) {
302 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
303 h_vbr_scale = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
306 // System.out.println("VBR:"+xing+" Frames:"+ h_vbr_frames
307 // +" Size:"+h_vbr_bytes);
309 } catch (ArrayIndexOutOfBoundsException e) {
310 throw new BitstreamException("XingVBRHeader Corrupted", e);
313 // Trying VBRI header.
314 String vbri = "VBRI";
317 System.arraycopy(firstframe, offset, tmp, 0, 4);
319 if (vbri.equals(new String(tmp))) {
325 h_vbr_toc = new byte[100];
328 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
329 h_vbr_bytes = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
332 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
333 h_vbr_frames = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
335 // System.out.println("VBR:"+vbri+" Frames:"+ h_vbr_frames
336 // +" Size:"+h_vbr_bytes);
340 } catch (ArrayIndexOutOfBoundsException e) {
341 throw new BitstreamException("VBRIVBRHeader Corrupted", e);
345 // Functions to query header contents:
350 public int version() {
363 * Returns bitrate index.
365 public int bitrate_index() {
366 return h_bitrate_index;
370 * Returns Sample Frequency.
373 public int sample_frequency() {
374 return h_sample_frequency;
381 public int frequency() {
382 return frequencies[h_version][h_sample_frequency];
394 * Returns Protection bit.
397 public boolean checksums() {
398 if (h_protection_bit == 0)
407 public boolean copyright() {
414 public boolean original() {
421 * @return true if VBR header is found
423 public boolean vbr() {
430 * @return scale of -1 if not available
432 public int vbr_scale() {
439 * @return vbr toc ot null if not available
441 public byte[] vbr_toc() {
446 * Returns Checksum flag. Compares computed checksum with stream checksum.
449 public boolean checksum_ok() {
450 return (checksum == crc.checksum());
453 // Seeking and layer III stuff
455 * Returns Layer III Padding bit.
457 public boolean padding() {
458 if (h_padding_bit == 0)
473 * Returns Mode Extension.
476 public int mode_extension() {
477 return h_mode_extension;
480 // E.B -> private to public
481 public static final int bitrates[][][] = { { { 0 /* free format */, 32000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 176000, 192000, 224000, 256000, 0 }, { 0 /*
484 */, 8000, 16000, 24000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0 }, { 0 /*
487 */, 8000, 16000, 24000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0 } },
489 { { 0 /* free format */, 32000, 64000, 96000, 128000, 160000, 192000, 224000, 256000, 288000, 320000, 352000, 384000, 416000, 448000, 0 }, { 0 /*
492 */, 32000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 160000, 192000, 224000, 256000, 320000, 384000, 0 }, { 0 /*
495 */, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 160000, 192000, 224000, 256000, 320000, 0 } },
497 { { 0 /* free format */, 32000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 176000, 192000, 224000, 256000, 0 }, { 0 /*
500 */, 8000, 16000, 24000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0 }, { 0 /*
503 */, 8000, 16000, 24000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0 } },
507 // E.B -> private to public
509 * Calculate Frame size. Calculates framesize in bytes excluding header size.
511 public int calculate_framesize() {
514 framesize = (12 * bitrates[h_version][0][h_bitrate_index]) / frequencies[h_version][h_sample_frequency];
515 if (h_padding_bit != 0)
517 framesize <<= 2; // one slot is 4 bytes long
520 framesize = (144 * bitrates[h_version][h_layer - 1][h_bitrate_index]) / frequencies[h_version][h_sample_frequency];
521 if (h_version == MPEG2_LSF || h_version == MPEG25_LSF)
522 framesize >>= 1; // SZD
523 if (h_padding_bit != 0)
527 if (h_version == MPEG1) {
528 nSlots = framesize - ((h_mode == SINGLE_CHANNEL) ? 17 : 32) // side
531 - ((h_protection_bit != 0) ? 0 : 2) // CRC size
533 } else { // MPEG-2 LSF, SZD: MPEG-2.5 LSF
534 nSlots = framesize - ((h_mode == SINGLE_CHANNEL) ? 9 : 17) // side
537 - ((h_protection_bit != 0) ? 0 : 2) // CRC size
544 framesize -= 4; // subtract header size
549 * Returns the maximum number of frames in the stream.
552 * @return number of frames
554 public int max_number_of_frames(int streamsize) // E.B
559 if ((framesize + 4 - h_padding_bit) == 0)
562 return (streamsize / (framesize + 4 - h_padding_bit));
567 * Returns the maximum number of frames in the stream.
570 * @return number of frames
572 public int min_number_of_frames(int streamsize) // E.B
577 if ((framesize + 5 - h_padding_bit) == 0)
580 return (streamsize / (framesize + 5 - h_padding_bit));
587 * @return milliseconds per frame
590 public float ms_per_frame() // E.B
593 double tpf = h_vbr_time_per_frame[layer()] / frequency();
594 if ((h_version == MPEG2_LSF) || (h_version == MPEG25_LSF))
596 return ((float) (tpf * 1000));
598 float ms_per_frame_array[][] = { { 8.707483f, 8.0f, 12.0f }, { 26.12245f, 24.0f, 36.0f }, { 26.12245f, 24.0f, 36.0f } };
599 return (ms_per_frame_array[h_layer - 1][h_sample_frequency]);
607 * @return total milliseconds
609 public float total_ms(int streamsize) // E.B
611 return (max_number_of_frames(streamsize) * ms_per_frame());
615 * Returns synchronized header.
617 public int getSyncHeader() // E.B
619 return _headerstring;
622 // functions which return header informations as strings:
624 * Return Layer version.
627 public String layer_string() {
639 // E.B -> private to public
640 public static final String bitrate_str[][][] = { { { "free format", "32 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s", "176 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s", "forbidden" }, { "free format", "8 kbit/s", "16 kbit/s", "24 kbit/s", "32 kbit/s", "40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s", "forbidden" }, { "free format", "8 kbit/s", "16 kbit/s", "24 kbit/s", "32 kbit/s", "40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s", "forbidden" } },
642 { { "free format", "32 kbit/s", "64 kbit/s", "96 kbit/s", "128 kbit/s", "160 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s", "288 kbit/s", "320 kbit/s", "352 kbit/s", "384 kbit/s", "416 kbit/s", "448 kbit/s", "forbidden" }, { "free format", "32 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "160 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s", "320 kbit/s", "384 kbit/s", "forbidden" }, { "free format", "32 kbit/s", "40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "160 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s", "320 kbit/s", "forbidden" } },
644 { { "free format", "32 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s", "176 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s", "forbidden" }, { "free format", "8 kbit/s", "16 kbit/s", "24 kbit/s", "32 kbit/s", "40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s", "forbidden" }, { "free format", "8 kbit/s", "16 kbit/s", "24 kbit/s", "32 kbit/s", "40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s", "forbidden" } }, };
649 * @return bitrate in bps
652 public String bitrate_string() {
653 String kbs = " kb/s";
655 return Integer.toString(bitrate() / 1000) + kbs;
657 return bitrate_str[h_version][h_layer - 1][h_bitrate_index];
664 * @return bitrate in bps and average bitrate for VBR header
667 public int bitrate() {
669 return ((int) ((h_vbr_bytes * 8) / (ms_per_frame() * h_vbr_frames))) * 1000;
671 return bitrates[h_version][h_layer - 1][h_bitrate_index];
676 * Return Instant Bitrate. Bitrate for VBR is not constant.
678 * @return bitrate in bps
680 public int bitrate_instant() {
681 return bitrates[h_version][h_layer - 1][h_bitrate_index];
687 * @return frequency string in kHz
690 public String sample_frequency_string() {
691 switch (h_sample_frequency) {
693 if (h_version == MPEG1)
695 else if (h_version == MPEG2_LSF)
700 case FOURTYFOUR_POINT_ONE:
701 if (h_version == MPEG1)
703 else if (h_version == MPEG2_LSF)
709 if (h_version == MPEG1)
711 else if (h_version == MPEG2_LSF)
724 public String mode_string() {
729 return "Joint stereo";
731 return "Dual channel";
733 return "Single channel";
741 * @return MPEG-1 or MPEG-2 LSF or MPEG-2.5 LSF
744 public String version_string() {
750 case MPEG25_LSF: // SZD
751 return "MPEG-2.5 LSF";
757 * Returns the number of subbands in the current frame.
759 * @return number of subbands
761 public int number_of_subbands() {
762 return h_number_of_subbands;
766 * Returns Intensity Stereo. (Layer II joint stereo only). Returns the number
767 * of subbands which are in stereo mode, subbands above that limit are in
768 * intensity stereo mode.
772 public int intensity_stereo_bound() {
773 return h_intensity_stereo_bound;
776 public void setSideInfoBuf(SideInfoBuffer sib) {
780 public void setBitReserve(BitReserve br) {
784 public SideInfoBuffer getSideInfoBuffer() {
788 public BitReserve getBitReserve() {
792 public int getIdx() {
796 public int setIdx(int idx) {
797 return this.idx = idx;